The overall objective of this Program Project is understanding the sequence organization of the animal genome. The Project unites efforts of five laboratories, and is directed into three Task Areas: I) Development of new technology for analysis of DNA sequence organization; II) Organization of specific genes and gene families; III) Repetitive sequences, transposable sequence elements, and evolution of the genome. The specific methods to be developed (Task Are I) include new procedures for two-dimensional electrophoresis of DNA fragments, for direct selection of cosmid and cDNA clones, for determining the reiteration frequency of repeated sequences, and for mapping repeat length and spacing in cloned DNA fragments. Among the specific genes and families to be studied (Task Area II) are the actin genes of echinoderms and Drosophila genes for several mammalian growth factors, genes for the opsin visual proteins of the Drosophila eye, and genes for the ion channels of mammalian nerve and muscle. Proposals focussed on genomic repeats, sequence element transposition, and evolution (Task Area III) include investigations of evolutionary transposition of repetitive sequences in echinoderm and human DNAs the origins of actin gene subfamilies in sea urchin evolution, and further sequence organization studies in cloned mammalian DNA fragments. This program Project operates in a highly cooperative manner in which enzymes required for manipulation of nucleic acids are prepared by a Core facility, and equipment, information, technology and results are freely shared among the participating laboratories.